Phosphorus Has an Atomic Number of 15, So What Is

Multiple Choice

Phosphorus has an atomic number of 15, so what is the distribution of its electrons?

A) The first energy level has eight and the second has seven.
B) The first energy level has two, the second has eight, and the third has five.
C) The first energy level has two and the second has 13.
D) The first, second, and third energy levels have five electrons each.
E) The electron arrangement cannot be determined from the atomic number alone.